while the rest of the cap just seems to be maturing is typical of A. onusta. I can’t think of another amanita that “gives up on its gills” so quickly.
The name “onusta” means “loaded,” and I always thought that the warts on the cap looked like little piles of gunpowder measured out for a muzzle-loading rifle.
Damon is correct about the (usually) distinctive bulb and base of stem. I have found very much oversized specimens in which the volva was much more powdery and spread out over a larger surface and the recurved scales were not so common on the upper part of the bulb. Those scales get made because the decaying and then drying volva glues little areas of the stem surface together so they can’t expand when the flesh inside the stem (that is connected to these glued-solid spots) expands. The amanita stem is essentially a water-powered pile-driver in reverse (a cap-raiser). The vertical force is (relatively speaking) tremendous and cannot be denied…even of the stipe gets “torn up” in the process.